Multiple-unit switch-control system.



No. 832,926. PATENTED OCT. 9, 1906; P. H. SHEPARD. MULTIPLE UNIT SWITCH CONTROL SYSTEM.

APPLIGATION FILED FEB'12,1904.

5 SHEETSSHEET 1 WITNESSES.-

No. 882,926. PATENTED OCT. 9, 1906. F. H. SHEPARD. MULTIPLE UNIT SWITCH CONTROL SYSTEM.

APPLICATION FILED FEB.12,1904

K Fig. Z.

5 SHEETSSHEET 2.

kM-W W WITNESSES.-

Y 4 6' 6% I 7 A'TTORNEY.

PATENTED OCT. 9, 1906. P. H. SHEPARD. MULTIPLE UNIT SWITCH CONTROL SYSTEM.

APPLICATION FILED IEB.12.1904.

5 SHEETS-SHEET 3- VENTOR.

A'TTORA EY.

WITNESSES; f;

No. 832,926. PATENTED OCT. 9, 1906.

P. H. SHEPARD. MULTIPLE UNIT SWITCH CONTROL SYSTEM.

APPLICATION FILED FEB.12,1904.

5 SHEETSSHEET 4.

Fig. 4.

c u'. m n n m u I IIIHIII IIIMHII m Q m WITZ VESSES- 1 VENTOR.

' Jami 85, 616m M Q Q A'TTORNEY.

No. 832,926. PATENTED OCT. 9, 1906.

P. H. SHEPARD. MULTIPLE UNIT SWITCH CONTROL SYSTEM.

APPLICATION FILED FEB.12.1904.

5 SHEETS-SHEET 5.

Fig. 5

WITNESSES; I V TVTOR.

A'TTORNE Y.

UNITED STATES P 'rEN'r OFFICE.

FRANCIS H. SHEPARD, OF NEW YORK, N. Y., ASSIGNOR TO GEORGE WESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA.

MULTIPLE-UNIT SWITCH-CONTROL SYSTEM.

Specification of Letters Patent.

Patented Oct. 9, 1906.

Application filed February 12, 1904. Serial No- 193,356. v

a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented a new and useful Improvement in Multi le-Unit Switch- Control Systems, of which t e following is a specification.

My invention relates to methods of controllingelectric motors; and it has for its object to provide a method which shall obviate interruption of the motor-circuits between starting and full-speed running conditions and all abrupt changes in torque and speed.

The most common method of supplying energy to large numbers of electric motors is from supply-circuits of constant potential,

and it is generally desirable when starting motors under load to preserve the amount of current supplied thereto substantially constant and obtain a substantially constant torque from the motors during acceleration in speed. Single motors are commonly op-' erated by placing external resistances in series therewith and successively cutting out or shunting portions thereof until the motors have attained full speed, more or less energy being thus absorbed in the external resist-- a The current flowing through the resistance ances.

Part of the loss occasioned by supplying current through external resistance may be obviated by utilizing the electromotive forces generated by the motors themselves,-a method commonly employed in the control of two motors which are mechanically connected to the same load, the electromotive forces generated in the two motor-armatures being added together until the motors have attained half-speed. From this point full speed may be attained by various methods, one of which involves the opening of the motor-circuits completely, changing the relations of the motors with reference to eachother, and inserting a resistance in series therewith, portions of which are successively cut out of circuit or shunted until full speed is reached under the existing conditions of load and supply voltage. Another method consists in shunting one of the motors, cutting it out of the circuit, and then connecting it in parallel with the other motor, suitable resistance. also being placed in the circuit,

which is gradually cut out as the motor at tains .full. speed. The first of these two methods is objectionable, because of the interruption of the supply of current to the motors and the consequent cessation of torque, while in the latter method one of the motors is unduly overloaded, and in the control of large motors the necessary refinement of adjustment of'the resistance often renders the method ractically prohibitive. Single motors may e similarly controlled by supplying the armatures with two windings and treating each winding as if it were placed on a separate armature.

In my invention the current through each motor is preserved substantially constant, depending only upon the refinement ofthe resistance gradations. In the control of two motors or of a single motor having a twocircuit armature-winding half-speed under existing conditions of load and voltage at the motor-termi'nals is attained by the manipulation of pairs of resistances inserted between the motor-terminals, at which speed and motor circuits is adjusted to be the same for a given load, and it is obvious, therefore, that if this common junction is opened the motors will be in independent circuits between the supply-mains runnin at half speed .with approximately half the voltage of the supply-circuit impressed on their terminals, full speed being attained by gradually shunting the resistances which are in series with the motors.

My invention is illustrated in the accompanying drawings,- in which Figure 1 is a diagrammatic view of a complete system or" control employing two motors organized in accordance therewith. Fig. 2 represents diagrammatically the conditions of the motor-circuits for each of the positions of the master-controller. Fig. 3 is a diagrammatic view of a complete system of control employing four motors, and Figs. 4 and 5 represent diagrammatically the conditions of thernotor-circuits for each of the positions of the master-controller of Fig. 3.

ICC

connected, respectively, in series with me- I tors 3 and 4, the resistance 1 being connected to one terminal of the field-magnet 5 of the motor 3 and the resistance 2 to one terminal of the armature 6 of the motor 4. One terminal of the field-magnet 7 of the motor 4 is connected to the ground G, while one terminal of the armature 8 of the motor 3 may be connected to a trolley T by means of a switch 9. A switch 10 intervenes between the free ends ofthe resistances 1 and 2, and a switch 11 is located in a circuit between taps 12' and 13 to the said resistances. Taps I4 serve to subdivide the resistances 1 and 2, switches 15-, 1'6, 17, 1 8, 19, andbeing adapted to connect successive taps, substantially as shown. A switch 21 'iS located in a circuit between the ends of the resistances 1 and 2, which are respectively connected to the motors 3 and 4, a switch 22 intervenes in'a conductor between the tap 13 and the trolley T, and a switch 23 intervenes in a conductor between the tap 12 and the ground Gr. As

here shown, the switches are operated by means 'of magnet-coils 24,- one terminal of each of which is connected to a common wire 25, connected with the negative terminal of a battery 26, and the other terminals of which are connected ,to the proper contact-fingers 27 of a master-controller, the drum 28 of which is shown diagrammatically developed into a plane.

The method of control comprising my invention may be best understood by a consideration of the conditions of the motor-circuits for each of the positions of the master-controller drum 28. When the controller-drum occupies the position a, the magnet-coils of the switches 9 and 10' are energized, and thereby eflect closure of said switches, the

corresponding conditions of the motor-circuits being shown at a in Fig. 2. In position b of the master-controller drum the switch 11 is closed, a part of each of the resistances 1 and 2 being thereby shunted, as indicated at b in Fig. 2'. Switches 1 5 and 1 6 are closed when the master-controller drum is moved to position 0, and the switches 17 and 18 are closed when the controller moves to position (1, parts, of the resistances 1 and 2 bein' shunted by means of these operations. oth of the resistances 1 and 2 are entirely shunted in position e of the controller-drum, since switch 21 is closed by this 0 eration, while for position f of the contro er-drum the motors 3 and 4 are in full series, as shown at f in Fig. 2, since the switches 10', 11, 15, 16, I7, and 18 are now in open position. Position g is a transitional notch, the switches 22' and 23 being closed, as indicated at g in Fig. 2, and intermediate points in the resistances 1 and 2 being thereb connected, respectivelyto the trolley T an 1 the ground G. I In the next poof resistances 1 and 2, so that in the sition 7c the motors 3 and 4 are connected insition the switch 21 opens, leaving the motors connected independently to the line, with a resistance in series with each, as shown at h. The succeeding ositions t, j, and 7c of the master controller s unt ortiions a podependently to the line without resistance in circuit. It is evident that the conditions of. the motor-circuits have been varied from starting to full-speed running without interruption and without abrupt changes in the torque of the motors during any step, even I that between full series connection of the motors and the first independent connection thereof. It is also obvious that both motors .need not be mounted on the same car, as

with very little modificationthe motors may be controlled independently or together, as desired, since each motor is provided with its own resistance element connected directly thereto.

In the control of'four motors, as shown in Fig. 3, the arrangement of the switches for each of the pairs of motors 2'9 and 30'- and 31 and 32 are very similar to those described for the'two-motor equipmentthat is, the switch 33 intervenes between the trolley T and the motor 29 and switches 34 and 3-5 intervene, respectively, betweenthe ends of the resistance elements 36' and 37 and between the elements 38 and 39. Switches 40 and 41 are provided, respectively, between one end of the resistance 37' and the armature-terminal of the motor 30- and between the field-magnet terminal of'the motor 31 and one terminal of the resistance element 38', and a switch 42 is provided between the fieldmagnet terminal of the motor 30 and the armature-terminalof the motor 31. Switches 43 and 44 intervene in circuits, respectively, between one terminal of the resistance element 37 and the field-magnet terminal of the motor 30' and between the armature-terminal of the motor 31 and one terminal of the resistance element 38, and switches 45 and 46 are provided, respectively, inthe circuits between the field-magnet terminal of the motor 29 and the armature-terminal of the motor 30 and between the field-magnet terminal of the motor 31 andthe armature-terminalof the motor 32. p

The resistance elements 36, 37, 38, and 39 are res ectively provided with taps 47, 48,

50, an 59 at suitable points therein, and switches 51 and 52, respectivel intervene between the taps 47 and 48 and between the taps 49 and 50. The remaining portions of each of the resistance elements are suitably subdivided by means of taps, which may be connected by means of switches 53 to 64, in-

clusive, substantially as shown. Switches 65, 66, and 67 are provided in a circuit between taps 47 and 50, and switches 68 and 69 are respectivel provided between the tap '48 and the trol ey T and between tap 49 and -79 in circuits, res ectively, between the point 80 in the tro ey T and between the point 81 in the ground G.

All of the switches are operated by means of magnet-coils which w en energized actuate the armatures to which the switcharms are suitably secured, one terminal of each of the magnet-coils being. connected with the ne ative terminal of the battery 82 by means 0% the common return conductors 83, the other terminals of the said coils being properly connected to the contact-fingers 84 of a master-controller 85, having a rotatable drum 86, ada ted to engage at proper intervals with the ngers 84, the positive terminal of the battery 82 being also connected to one of the fingers 84.

' In the first position of the master-controller drum 86 only the switch 33 is operated; but in the second position switches 34, 35, 40, 41, and 42 are closed, the motors then being all in series with all of the resistance in circuit, as shown by the diagram 1) of In position 0 of the master-controller drum switches 51 and 52- are closed, short-circuiting the end portions of each of the resistance elements, and in the succeeding positions (1, e, and f of the controller-drum other portions of each of the resistance elements are short-circuited, due to the closing of the switches 53 to 64, inclusive, the entire resistance of the circuit being shunted in position 4 5 f. The motors are in full series for position g of the master-controller drum, the resistances being entirely shunted by the closing of the switches and 46, and in position it the resistance connections are entirely severed by the opening of the switches 34, 35, 51, 52, and 53 to 64 leaving the motors still in full series relation on what maybe termed a runningnotch of the master-controller. Position 1' is a transitional notch in which the switches 65, 66, 67, 68, and 69 are closed, connection between-the taps 47 and 50 of the resistance elements 36 and 39 being thereby provided and also connections from the ta 48 of the resistance element 37 to thetro ley T and from the tap 49 to the ground G, as shown at i in position 4. In position j of the controllerdrum switches 45 and 46 open and the motors and connected resistances are left in two in dependent circuits, each having two motors and the proper amount of resistance. In the succeeding positions k, l, and m portions of the resistances are shunted until in posi tion m the resistances are entirely out out of the circuits, leaving the motors in two sets hav' independent connection to the line. In position n switches 74 and 75 and switches '78 and 79 are closed, and in position 0 the switches 40, 41, 53 to 64, 65, 67, 68, and 69 are opened, leaving the motors connected to the line substantially as in position n. Position p of the controller-drum is a transitional notch in which the switches 43, 44, 70, 71, 72, and 73 are closed to provide connections between one terminal of the resistance element 37 and the field-magnet terminal of the motor 30, between the armature-terminal of the motor 30 and one terminal of the resistance element 38, between the taps 47 and 48 and the ground G, and between the taps 49and 50 and the trolle T, substantially as shown at p in Fig. 5.. en the master-controller drum is moved to position q, switches 42, 66, 74, and open, leaving all of-the motors independently connected to the line, with suitableresistance in series with each, as shown. at q in Fig. 5. In the succeeding positions 1, s, and t of the controller-drum portions of the resistance elements are shnnt' ed until, in position t, the entire resistance is shunted and the motors are all connected independently to the line with no resistance in circuit, this being the full-speed runningnotch of the motors.

Although I have shown electromagnetic means for operating the switches, it is to be understood that pneumatic devices which are electrically controlled or any other satisfactory means may be employed for that purpose. It is evident, too, that the system which I have described is well suited to the control of trains in which several cars are provided with motors by simply providing proper connections between the cars so that the switches on all cars may be governed in parallel.

I claim as my invention- 1. The method of controlling two electric motors which consist in the following steps: connecting the motors in series with each other and with resistances located between them, shunting portions of the resistances and finally the whole of them, severing the connections between the resistances, con necting points of the resistances to the line conductors, removing the said final shunt connection to' the resistances, and successively shunting portions of the resistances.

2. The method of controlling two electric motors which consists in the following steps: connecting the motors in series with each other and with two resistances located between them, shunting portions of the resistances, shunting both resistances entirely,

IIO

resistances, connecting points in the resistances-respectively to the positive and negative line conductors, removing the said shunt connection to the resistances, and shunting the remaining portions of the resistances.

"3. The method of controllin two electric motors -which consists in the 0 lowing steps: connecting one terminal of each motor to "a line conductor and two ends of two resistances together, connecting to ether points in' the resistances, shunting t e remaining portions'of the resistances in suitable gradations, providing a connection from a terminal of one motor to a terminal of the other, severing all connections-of the resistances with each other,'connecting points in the resistances respectively to the positive and negative line conductors, severing the said'connection between the terminal of one motor and the terminal 'of the other and shunting the remaining portion 'of the resistsince in suitable gradations.

4. The method of operating electric motors in connection with resistances which consists in providing a shunt for the resistances, severing connection between them,

connecting points in the resistances respectively to the positive and negative line conductors and removing the said shunt to the resistances.

5. The method of control'lin two electric motors which consists in the following-steps: connecting the motors in series and with resistances located between them, shunting 'correspond'in portionsof the resistances and finally the w cle of them, severing the conneetions between the resistances, connecting points intermediate the ends of the resistances to the line conductoraromoving the 'said final shunt connection of the resistances, and successively shunting portions of the resistances.

'6! The method of controlling twoelectric motors which consists in the following steps:

' connecting the motors in series and with resistances located between them, shunting corresponding portions of the resistances and finally the whole of them, severing the connections between the resistances, connecting points intermediate the ends of the resistances to the line conductors, removing the said final shunt connection of the resistances, successively shunting portions *of the resistances, and finally shuntinga'll of the resistances.

7. The method of controlling four electric motors which consists in the following steps:

connecting the-motors in series with each other and with subdivided resistances, the first and second being connected respectively between the first and'second motors'and the third and fourth resistances between the third' and fourth motors, connecting points in the first and third resistances respectively to points in the second and fourth resistances, connecting one terminal of each of the first and third motors respectively to one terminal of each of the second-, fourth 'HlOtOI'S, severing all connectionslbetween the resistances, connecting a point in the first resistance with a point in the fourth resistance, a point in the second resistance 1200116 line conductor and "the corresponding point in the third resistance to the other line conductor, severing" the said connections between the first and secondmotors and between the third and fourth motors, succes sively shunting the remaining subdivisions andthird resistances respectively with terminals of the second and third motors, severing all connections between the motors, and successively shunting the subdivisions of the resistances.

8. The method of controlling a pluralit of electric motors which consists in the fo lowing steps: connecting the motors in series with each other and "with resistances arranged in pairs,- shunting the airs of resistances, connecting points int c resistances belonging toldifi erent pairs with each other and'points in the other two resistances to supply-conductors of opposite sign, and removing the shunt connection to the pairs of resistances.

'9. The method of controlling four electric motors which consists in the following steps: combining the motors, in series-connected pairs, independently to the line, connecting a terminal of each motor with resistances and the resistances' with supplyconductors, and severing-connections between the motors.

' T0. The method of controlling a plurality of electric motors, which consists in first connecting said motors in series with a like number of external resistances in seriesconnected pairs, removing'the external re-- sistances from the series circuit, connecting points In a resistance of each pair to line conductors and points in the remaining resistances together, severing connections between the resistances, again removing the resistances from the circuit, connecting points in each resistance-to line conductois, and

severi connections between the motors.

11. he method of controlling a plurality of electric motors, which consists in first connecting said motors in series with a like number of external resistances in series-connected g ans, removing the external resistances In testimony whereof I have hereunto sub om the senes circu t, connecting points in a scribed my name this 28th day of January, 10

resistance (if each pair to line conductorsfind 1904.

oints in t e remaming' resistances to ct er,

5 gain removing the'resistances from t he cir- FRANCIS SHEPARD cuit, connecting points in each resistance to Witnesses:

line conductors, and severing connections WESLEY G. CARR,

between the motors. O'r'ro S. SOHAIBER. 

